Failure to Launch

by Alan Moghaddam

The Houston Rockets are at a point of critical failure – or rather, they have reached a crux with more than one point of critical failure.

The Rockets’ record stands at 13-7 roughly a quarter of the way into the regular season. It has finally been long enough to shake off the “it’s too early to comment” crowd, and we can finally make some valid statement about this team long-term. To all appearances, things are not looking particularly spectacular for a team that entered the season with championship expectations.

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What is TPA?

by Alan Moghaddam

Chances are if you’re into sports you’ve seen the famed charts from @NBA_Math that feature overlapping pictures of NBA players in a conventional Cartesian plot with a line plotted on it (y=-x). Anything above the line is good, anything below is bad, and average values will tend to walk the line. The graph is a visual attempt to quantify some mystery statistic known as TPA.

This is a standard TPA graph from @NBA_Math

What is TPA?

This is something of a loaded question; the acronym TPA stands for “Total Points Added”. The basic idea behind it is that a player adds points on offense and defense. You then total these subsections to get TPA.

Unfortuantely, the definition above is rather incomplete. We now need to understand Offensive Points Added (OPA) and Defensive Points Saved (DPS), the components which make up TPA. The two subcategories are much more complex than TPA alone.

To get OPA and DPS, we need to use “Box Plus/Minus,” an all-in-one statistic created by Daniel Myers and hosted at basketball-reference.com. I promise we are almost at the bottom of the well here in terms of stat definitions. Box Plus/Minus is a relativistic stat that gauges a player’s impact on team performance when s/he is on the court. S/he again will have an impact on both defense and offense, so accordingly Box Plus/Minus can break down into two stats: Offensive Box Plus/Minus (OPBM) and Defensive Box Plus/Minus (DPBM). We can already see that TPA has the same structure as Box Plus Minus; both purport to measure a player’s impact on both ends of the floor. What is the difference between the two?

Equation 1. Calculation of TPA as a function of Defensive Points Saved and Offensive Points Awarded
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P.J. Tucker Looks to Secure the Bag

After two years as the Rockets’ stopper, P.J. Tucker is looking to secure the bag. Tucker has two seasons and $16.3 million left on his current contract, at the end of which he will be 36 years old. Tucker’s motivation in seeking a contract extension is entirely sensible; his market value is high, meaning he is deserving of a raise. Signing an extension now would also guarantee his income into the final phase of his career. Asking for an extension is the smart move for Tucker, but what should the Rockets do?

In the last four seasons, P.J. Tucker has compiled 17.3 Wins, an average of 4.3 per season. 14.4 of those wins (83.2%) have come on the defensive end, and Tucker is known by reputation around the league as a defensive specialist.

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